Apparatus for rolling threads into metal pipe



Feb. 16, 1954 Filed April 28, 1949 H. J. FINCH APPARATUS FOR ROLLINGTHREADS INTO METAL PIPE 6 Sheets-Sheet l INVENTOR HARRY J. FINCH v Feb.16, 1954 Nc 2,669,139

APPARATUS FOR ROLLING THREADS INTO METAL PIPE Filed April 28, 1949 6Sheets-Sheet 2 INVENTOR HARRY J. FlNcH Feb. 16, 1954 H. J. FINCH2,669,139

APPARATUS FOR ROLLING THREADS INTO METAL PIPE INVENTOR HARRY J. FINCH H.J. FlNCH APPARATUS FOR ROLLING THREADS INTO METAL PIPE Feb. 16, 1954 6Sheets-Sheet 4 Filed April 28, 1949 MWQN INVENTOR HARRY J.F|NCH 5 47, M

W JMmH Feb., 16, 1954 H. J. FINCH APPARATUS FOR ROLLING THREADSINTO-METAL PIPE Filed April 28, 1949 6 Sheets-Sheet 5 Feb. 16, 1954 H.J. FlNCH APPARATUS FOR ROLLING THREADS INTO METAL'PIPE Filed April 28,1949 I 6 Sheets-Sheet 6 INVENTOR Patented Feb. 16, 1954 UNITED .lS ENTsrPARA'rus-ro ROLLING THREADS INTO ETAL PIPE Harry-J, Finch, OiLGity,Pa., .assignor to Jones.\&- 'Laughlinl Steel Corporation, Pittsburgh,3a., a

corporation of Bennsylvania "Applicationi'April'28, 1949, SerialNo."90,071 L51Cl'aims. (01.1'80-6.)

pipeiand 'new' and: improved metal pipe having threads rrolled.thereinto whereby inrportant:--.advantages: both" in-the rolling, ofthe: threadsii-nto the;- pipe and in the structure rand. use. of -=.-thethreaded piper-are obtained.

Metal pipe of certain characteristics may be threaded .by rolling-Relatively thin-walled pipe -01" tubing and "heavier-walled pipe of'isufiicient ductility may he thus'threaded. For'purposes of :explanati-on' and illustration I shall discuss, the threading. ofthin-walled steel'tubing although mywinventioniis not limited in all Of'-itS1'aSp6CtS to the: threading. of such'tu-hingbut may be: otherwiseembodied? and practiced.

:Lengths of thin-walledsteel. tubing are-fastened togethervend toend';to make long tubes for variouspurposes, as, for example, so-call'ed-:shot hole vcasing. Desirably each. length. or-section issomewhauexpanded-at' one end so -that it'will telescope withthe--nnexpandedioppositeend; of a similar section and threads arerolledinto-the telescoping ends so that theymay be screwed together. Thethread rolling operationtisrapid and economical and fcrrelativel-ythin-walled pipe and pipe-*ofr-sufiicient ductility is far less costlythan cutting-threads by the conventional method moreover, astronger and.otherwisesuperior; product is produced.

It has heretoiorebeen proposed? to roll threads into thin-walled tubulararticles but the threads --l1lhih have been produced'have beenin-feriorand no practicable Way ofcthreading relatively long sectio-nsofv pipe has been developed. Ihaverdevised a mac-hine for rolling threadsinto metal pipe which :accomplishesthe. result in "a 1 highly accurate,efiect-ive and efiicient manner. I-:ha:ye also devised a method ofrolling threads into "metal :pipe whereby important advantages areobtained. :2 have also devised a new thread form of: importantlyincreased strengthuand efiiciency relatively to rolled threadsheretofore developed.

12in rolling threads into thin-Walled? steelttuhing iti-hasheretofore-been considered necessary to effect a partial shearing of themetal tosharply displace metal-substantially radially to form the--:threads. The result :has'heena lackof uniformity in :the threads,-:the thread dorm differing especially in articles: of: steelof-different characteristics, and being in any-Yevent subjectto earlyiailurecrepullinga out undersload. .lI-lhave discovered-whatthee-conception 171113 1 the z-srclled 2. threads should be formed by:a-w-shearingacticnafis fallacious and: that it is not necessaryto-.-so-.-torm them. On the contrary, I formz za vastly; superior andmore uniform thread through causing-a flow of themetal whileavoiding-anysubstantialsheaming action. -I*rotate the pipe genera-1v about itsaxiscand during such rotation simultaneouslyrenrgage the pipeinternallywand externally at; rad-i -ally-opposed portions-thereof andsqueeze rthe metal so as'to-vcause it to flow withoutanvsubstantialshearing to form threadsprojecting from one surface of thepipe while-deforming: the-opposite surface so thatmetal-throug-hout'the; en,- tire. thickness of the pipe is flowed-and reshaped duringthread formation. I, preierablyA-form--..-in the pipe bysimultaneous.internal and external rolling at radially [opposed.portions I thereof: ternal and external-alternately arranged groovesand projections in generally helical form and during the formingof suchgrooves-.-and;,-proiec tions somewhat ioreshortenthe-pipe and there.-

.aiiter flow the metal at-the groovesland projections without anysubstantial/shearingof' the metalrto dorm; av thread-at. one surface ofthe pipe. :Ldesi-rably form. in-thatway a thread 'whose side Walls oresubstantially parallel to-.each.other.

rolling into metal pipe threads: whosesside wallsare substantiallyparallel to cache-other]:

desirably r rotate thev pipe generally about -its axis and during suchrotationpress the: metal from the-.surface of the pipe oppositethesurface to bethreaded toward thesuriaceto the ,threaded,,.limitingthe metalfiow at thescrests ,of the incipient threads. andforcing theemetal laterally generallyparallel to the crests to: formgenerally. square corners on. the: threads. may dorm in vthe pipeagenerally helical corrugation.

..I. further provide a method of rollingvthreads into metal pipewcomprising engaging l-the r-pipe internally-and externally by rotatingdies which squeeze the r-metal. of the-pipe.-therebetween-and causerotation of the pipe (duringuthetthreading operation and hyoneof thedies flowing the metal withoutianysubstantialshearing of. themetaliintoa thread forming :cavityin. the; other.- die.

,I roll into metal pipe threadsof new-and: improved shape which-arevastly stronger than/the previous rolled .-threads: both' vrith respecttovpu-lli-ng out-and withrespect to failure under load. .I provide metalpipe having a! rolled thread atone surface thereof, the oppositesurtaceofthe pipe having a.- helical depression whose .dimension axiallyi ofthepipe at; its,-.bottom is not hover -about I radially opposite thecenter of the thread crest, and. a helical projection radially oppositethe thread throat and merging into the depression. The dimension axiallyof the pipe of the helical projection opposite the thread throat ispreferably at least one-third greater than the dimension axially of thepipe of the thread throat.

I further provide metal pipe having at one surface thereof a rolledthread whose sid walls are substantially parallel to each other, theopposite surface of the pipe having a helical depression whose dimensionaxially of the pipe at its bottom is not over about half the dimensionof the thread axially of the pipe, the depression being disposedradially opposite the center of the thread crest, and a helicalprojection opposite the thread throat whose dimension axially of the pipis at least one-third greater than the dimension axial ly of the pipe ofthe thread throat and merging into the depression. The side walls of thehelical depression are preferably inclined toward each other and theside walls of the helical projection are preferably inclined toward eachother and the depression and the projection preferably merge into eachother. Desirably the thinnest section at the thread is at least abouteighty per cent of the thickness of the pipe wall at a point removedfrom the thread.

So far as apparatus is concerned one of the fallacies of thread rollingapparatus as heretofore developed has been that the dies aremechanically forced together, virtually eliminating the possibility ofadequate metal flow to form a thread as above described. The machinedesign has been consistent with the fallacious theory that the metalshould be sheared during thread formation. Not only have I discoveredthat the metal should not be sheared during thread formation but I havealso devised improved apparatus for rolling threads into metal pipewhich insures proper metal flow. I employ hydraulic means for forcingtogether the dies which roll the threads into the pipe. By use of suchmeans I can attain a relatively smooth flow of the metal which is notpossible, or at least not regularly obtainable, with mechanicallyoperated dies.

In use of my apparatus as the dies are pressed together hydraulicallythe metal is first bent or corrugated during which time the tube issomewhat foresh-ortened. After a time, perhaps twenty or mor revolutionsof the dies, the metal begins to flow from the surface of the pipeopposite the surface to be threaded toward the surface to be threaded,but as the extent of flow of such metal is limited at the thread crestsby the thread forming die the metal then spreads or flows laterallygenerally parallel to the crests. Thus I am enabled to form with easeand accuracy threads Whose side walls are substantially parallel to eachother, e. g., threads of generally square contour. Moreover, I do sowithout greatly reducing the wall thickness at the threads, the thinnestsection at the threads normally being at least about eighty per cent ofthe thickness of the pipe wall at a point removed from the thread.

My thread rolling machine has other important features and advantages.One of the most important advantages is that I can With ease andaccuracy roll threads into the ends of relatively long sections of pipewhich has not been possible with thread rolling machines heretoforeavailable. To accomplish that advantage I desirably employ a guidewayfor approximately aligning a pipe for presentation of an end thereof tothe die means and also employ means engaging the opposite end 4 of thepipe moving the pipe along the guideway to present the first mentionedend of the pipe to the die means, there being means inclined to thehorizontal raising the pipe ends upon presentation of the firstmentioned end to the die means whereby to free the pipe from theguideway While the threads are being rolled thereinto. Desirably the diemeans and the pipe engaging means have pipe engaging portions unseatingth pipe from the guideway and freely supporting it upon presentation ofthe first mentioned end to the die means. The pipe engaging portions arepreferably rotatable with the pipe during rolling of y the threadsthereinto.

More specifically I provide, in a machine for rolling threads into metalpipe, rotary dies adapted respectively to be positioned inside andoutside a pipe end when the pipe end is presented thereto and toco-operatively roll threads into the pipe end, one of the dies having apipe engaging portion adapted to enter the pipe and to position the pipeend for action thereon by the dies, a guideway for approximatelyaligning a pipe with said portion and means engaging the opposite end ofthe pipe moving the pipe along the guideway onto said portion, said lastmentioned means having a generally conical portion adapted to enter thepipe and to unseat the pipe from the guideway as the pipe is moved intoposition to be acted upon by the dies.

I further provide, in a machine for rolling threads into metal pipe,rotary dies adapted respectively to be positioned inside and outside apipe end when the pipe end is presented thereto and to cooperativelyroll threads into the pipe end, one of the dies having a portion adaptedto enter the pipe to guide the pipe into proper relationship with thedies to be acted on thereby, a guideway for approximately aligning apipe with said portion and means for feeding pipes one by one to theguideway. I may employ pipe delivery means for delivering pipeslaterally into the guideway and means for delivering pipes one by onefrom the delivery means laterally into the guideway.

I I also provide, in a machine for rolling threads into metal pipe,complementary rotary dies adapted respectively to be positioned insideand outside a pipe end when the pipe end is presented. thereto and toco-operatively roll threads into the pipe end and means for rotating thedies at the same angular velocity in opposite directions to roll threadsinto the pipe end, said means rotating the inside die in a directionsuch that when the threads are formed in the pipe the threaded pipe willbe fed back off of the inside die upon slowing of the rotation of thepipe relatively to that of the inside die, the diameter of the outsidedie being greater than that of the inside die so that during rolling ofthe threads in the pipe end the outside die frictionally engages thepipe end and thereby exerts force on the pipe tending to prevent thepipe from backing off during formation of the threads.

I desirably provide means for maintaining the dies in relatively fixedaxial position during formation of the threads in the pipe. Such meansmay be in the form of portions of the dies which move intointerengagement when the dies are relatively moved toward each other.One of the dies may have a radial flange and the other may have a radialgroove receiving the radial flange of the first mentioned die.

The dies preferably have co-operating por- "positioned?-forz-abutmentiwitheaichoother upon predetermined movemeht of the' dies toward e'aclrdther=whereby t0 limit ithevektent of action-of the'dies-nrithe pipe.The cradialldimensions" of 'the fiang'eiand groove above; referredltomaybe-proportioned so th'at the flangebottoms in "the grooveuponpredetermined'smovement of the dies toward' each other whereby tolimit the extentof actiomof thedies'on theipipe.

The radial -flange may be on the insidei 'die and may be po'sitioned to'wbe-z engaged =by-' the pipe ondtoactasa stop "to "limit the'extent to-which the pipeend passes over the insided-ie.

I have"referred above to the fa'ct that L prefer to employ hydraulicmeans #for relatively moving the dies toward and away from 1 eachother"orttransversely of the 1 axes thereof. EOne of the dies;preferably the inside die, :rnay-be mounted for rotation about a fixedaxis arid the "othcr' die'may be mounted on a support m'ovabletransversely of the axes'of the dies to- -pro videdorpressing-theseconddie against the outside 0f the pipe end so I that the second the "rollsthreads 'into -the pipe end co oper-atively with the first' mentioneddle. T Either die may be the .thread formingdie in any particular case,the other die being the "co-operating die which causes the metal to flow4 as above described-"into the thread: forining cavity' or the threadforming :die. J in threadingapin- *end 'the'thread forming idieiistheout'side die while in th-reading a box tend the? thread forming die isthe inside die.

"The support for' theoutside die is preferably pivotally -mountedon'abasa'thebase' being movable'genera'lly toward and-"away from theinside die and means *b'eing provided "for "ma intaming the support in-desired angular position a-bout'its pivotal mounting'on' -the base.Means are "preferably also provided for adj u'stably :positi'oningthebase in the-d'i rection oi itsmov'ement relatively toi the means for'moving itgenorally toward and away' from the inside die.

r-provide for controlledrelativelyslow movement of "the dies 'toward aeach other during a thread forming operation andrela tiv'elv'rapidmovement of the-dies awayiromeach other. I desirably employ hydraulic"means for relatively moving the dies toward each other and throttlemeans operable to limit the "flow of fluid inthe hydraulic means"whereby to determine the speed of-m'ovement'of the dies toward eachother. "I may employ a. hydraulically operable piston 'for relativelymoving the dies toward each'otherand thethrottle means" may limit theflow of fluid from in front Of the piston. The hydraulic system is"preferably'such that the throttle means functionon'lywhile'the dies'arebeing moved towardeachoth'er and notwhile they arelbeing moved awayfrom each other. "Thusby adju'stment of the throttlemeans the :movementor the dies"towardeach'other'inay' be controlled as desiredwithoutaffecting the rapidity of the movement of the dies away from eachother.

.I preferably provide roller means. rotatively supporting the inner'dieagain'st the pressure exerted thereon through the1pipe'b-y"the outerdie. LThe inner die may have-a raiditillyoutwardly open I grooveadjacent but I axially removedfr'om the thread forming. portionthereofand supporting means comprising'aapluralityjf rollers may engage the diewithin the ,groove to support it. against the: pressure exerted thereonthrough-'thegpipe by the second die. ".Means are preferably providdf-for ladiustably. positioning 6 Zthermolier inneans toward 5 and lawayffrom the second die.

aI'he .thread iormingzrdiesi'haver complementary metal i forming races,none 1 for: the faces having thereorraa: helical imetaliorming'proa'ection whose side walls may be? substantiallyparallet-to-each otherzarid thelother of said faces having"- thereon ahelical metal 1 forming projeotion whose side walls-areinclined1toreachother; which inclined side'fwalls extendrsubstantially:-to -thecrest of the second:mentionedfprojection, the projections being inaxiallyr'staggered relation. "The inclined side iwalls zspref'erably'ha've rounded corners at the" :top: andztbottom extremities thereoffacilitating'i the idesiredimetaliflow. 'IYhe iace' of thenonethreadtforming :die preferably 'has' thereona-.zhelicalz;metalrforming projection whose dimension axiallyrof thepipe T at "its crest is not overrabout half lthe dimension of themetal-formingzprojection :ofl-thertnread' forming die axially of: the!pipe.

18y the.improvements-above referred to- Iprovidegreatlyfi-mprovedithreaded pipeathigh speed andl'ow co'st and ofgreater uniformity-than pipe-with rolled threads heretofore produced.Certain of any:improved features may be-.zused without others but" Ipr'efer ii to include all of my. improved: apparatus features in -a'single-machine. lsucliuazmachine is shown inthe accompanying drawings.1' Other d'etails, objects and advantagesofthe invention w'ill becomeapparent as the iollowing' desciiiption of them-alanine shown intheidrawings;constituting apresent preferred embodiment ot my apparatusinvention, and of my improvec'iimethod and product, or which latter apresentpreferred embodiment is also shown in the drawi ngs, proceeds.

In the drawings Figure 1*is airagmentary elevationalview of theportion'of theapparatusfor feeding pipes tothe thread rollingdies;

Figure'z is avertic'alcross sectional view taken on the line 11-41-01?Figure 1;

Figure 3 is a vertical crosssectional view somewhat similar to Figure2"but to smaller scale and lookingdn the" opposite "direction so' as toshow a" portion; of the thread rolling means, 'theJngure being takenonthe line"III--III of Figure 4;

Figure 4 is asomewhat:diagrammatioiragmentary elevational view of theportion of the machine forrolling threads into. pipes, the portionoftheappara'tus shown in'Figuree being positione'dflto the left of the.portion of the apparatus shown in'Figure' 1, part of the apparatus,however; beingshown' in both of Figures 1 and 4;

Figure. 5 is an enlarged-fragmentary detail View partly inJelevationiand. partlyin vertical cross section showing the" thread rolling diesand the mechanism' for operating them;

Figure '6 .is a? fragmentaryelevational viewnof the apparatusrshown.imFigure. 5 .as viewed from the right-hand. end ofifE'iguref 5;

"Figure 7 is a fragmentary elevational view to enlargedscale showing. aportion of. the structure shown in-i Fliguress;

zmy ii-nventionaand IFi'gure; ,1 L .jsaaa; greatly;enlargedzidiagrarmshow ing the shape of the dies and the thread formedthereby.

Referring now more particularly to the drawings and especially toFigures 1 and 4, the apparatus shown comprises pipe feeding apparatuswhich is shown in Figure 1 and apparatus for rolling threads into pipeends which is shown in Figure 4. The feeding apparatus comprises asupporting structure 2 comprising an I-beam 3 upon which is carried amember i adapted to be bolted to the I-beam 3 at desired adjustedlocations along the I-beam by bolts 5. The member 4 carries at its lefthand end viewing Figure 1 one of a pair of co-operating V-shaped guides6, the two guides 6 being in horizontal alignment and together formingan upwardly open V- shaped guideway for positioning pipes forpresentation to the threading dies. The other of the guides 6, shown atthe left-hand end of Figure l and at the right-hand end of Figure 4, iscarried by the main frame I. of the machine.

There are also provided two generally angleshaped support members 8, onecarried by the member 4 and the other by the main frame T, whichtogether constitute an inclined chute or trough for delivering pipes tothe guideway 5, b. The members 8 are adapted to be spaced apart adistance determined by the length of the pipes being threaded so thatthe respective pipe ends are supported by the respective members 8. Themember 4 is moved along the I-beam 3 to position the member 8 carriedthereby appropriately relatively to the other member 8 which is mountedin fixed position on the main frame so that pipes delivered to the upperend of the chute or trough 8, 8 will be supported thereby at their endsand will roll down by gravity toward the guideway 6, 6.

Also carried by the member 4 is a guide bracket 9 for guiding a rod iscarrying at its left-hand extremity, viewing Figure 1, a member H freelyrotatable on the rod. The bracket 9 is constructed and arranged so thatthe member H is approximately aligned with the guideway ii, ii as willpresently be described.

Also carried by the I-beam 3 is a bracket it to which is pivoted at IS afluid pressure cylinder l4 within which operates a piston having apiston rod 15 connected at [B with the end of the rod H3. The bracket [2may be adjusted along the I-beam 3 as required.

There are provided two similar pipe actuating members ll, one pivoted at18 to a bracket [9 carried by the I-beam 3 and the other pivoted at 2tto a bracket 2! carried by the frame 1. Each of the actuating members ITis operated by a piston in a, fluid pressure cylinder 22, means beingprovided as will presently be described for operating the pistons in thetwo cylinders 22 simultaneously. The respective cylinders 22 arepivotally mounted on their brackets by pivots 23 and their respectivepiston rods 24 are pivoted to the respective actuating members I! at 25(Figure 2) Each of the actuating members I! has a generally upwardlyextending portion 26 and a generally downwardly extending portion 27.Upon pivotal movement thereof about the axis of its pivot pin in theclockwise direction viewing Figure 2 through action of the piston in thecorresponding cylinder 22 the portion 26 swings downwardly and theportion 21 swings upwardly from the position shown in the drawings.Movement of the actuating members I! in the counterclockwise directionviewing Figure 2 is limited by contact of the foot of the portion 21with the upper surface of its supporting bracket.

The two dies for rolling threads into the ends of the pipes aredesignated respectively by reference numerals 29 and 39 (Figure 5). Thedie 29 is adapted to be disposed inside the pipe end when the pipe endis presented to the dies and the die 30 is adapted to be disposedoutside the pipe end. The die 29 has a projection 3| adapted to enterthe pipe and an inclined annular shoulder 32 between the projection 3!and the die proper. The member H also has an inclined annular shoulder33. The die 29 is mounted for rotation about a fixed axis and that dieand the member I! are coaxially mounted. The die 29 has a radial flange34 which serves a number of purposes, one of those purposes being tostop and position the pipe when introduced over the die 29.

Before proceeding with a detailed description of the dies and theiroperating mechanism it may be desirable to describe the operation of themechanism for feeding the pipes one by one to the dies. The pipes arefed onto the inclined chute 8, 3 by any suitable means, as, for exampie,from a hopper or by hand. In any event, a supply of pipes iscontinuously provided on the chute 8, 8, the pipes rolling down thechute by gravity and contacting one another as shown in Figure 2. Whenthe actuating members I! .are in the position shown in Figure 2 theyrestrain the pipes from rolling down the chute with the foremost pipe onthe chute in position A. When the cylinders in the pistons 22 are movedup- War-dly by the means for synchronously operating such pistons, whichwill be described below, the members I? are turned in the clockwisedirection about the axes of the pivots l8 and 20 until the portions 26thereof pass below the level of the chute whereupon the foremost pipe onthe chute moves by gravity from position A to position B in Figure'2,the remaining pipes following down the chute by gravity. The foremostpipe is arrested by the stop or stops 28 when it reaches position B.When the pistons in the cylinders 22 are moved downwardly the members i!turn counterclockwise and the portions 26 thereof lift the foremost pipeover the stops 28 so that it rolls down the chute, at the same timepreventing the pipes behind from rolling down. The foremost pipe rollsdown the chute and drops into the guideway E, 6.

When a pipe is lying in the guideway 6, i3 its axis is slightly lowerthan the common axis of the die 29 and the member H as shown in Figure2, wherein the pipe is designated P. With a pipe resting in the guideway6, 5 the piston in the cylinder I4 is moved toward the left viewingFigure 1 causing the member H to engage the end of the pipe remote fromthe dies and exert pressure thereagainst toward the left or toward thedies. It should be mentioned that in the embodiment shown the box endsof the pipes are being internally threaded. The member ii pushes thepipe along the guideway so that the box end of the pipe moves over theprojection 3| of the die 29. The inclined shoulders 33 and 32 engage thepipe ends and lift the pipe slightly so that as it is presented to thedies both ends are raised from the guideway and the pipe is supportedentirely by the dies and the member H. When the pipe is in position tobe operated upon by the dies its forward or box end is against theflange 34 and its rearward or pin end is against the shoulder 35 of themember I I. While bers' IT are -turnedin the-clockwise direction;

their portions 21 lifting the threaded-pipe up" out of the-'guideway 6,B-and discharging it tothe'left'yiewing Figure 2.- At the' sametimeanother pipe rollsdown the chute against the stop-or stops 28 i as-above' described ready forrepetition "of "thecycles Referring now moreparticularlyto themechanism for supporting and operating the dies-29 and30; the die 294s disposed on the end'of a sliaft-' 36*rotatablymounted'in'bearings 31- inthe machine frame (Figure- 5)-.- The shaft36-is adapted to be rotated bya suitable source of powerthrough acoupling '38; The die-29-may" be formed as an *integral "part'of theshafti36 ormay be removably-attached to the shaft so" that differentsized dies maybe selectively used with'the same shaft.

Fixed to the-shaft-"iiii isa-gear39. The gearx' 39 meshes-with a gear 40fmountedsonanstub' shaft M-r The gear'flfl in turn meshes with a gear42fixed to' a, shaft 43 which is connected through afieXibIe"coupling 44"with ashaft 45; M to'whic'h is fixed-a'gear'Mi The gearidtimeshes witha gear 41 fixed to a shaft'48.whichicarries. thedie 3B;- The shafts 45andi'48 are tjournaled in' asupport 49 *which as :shown' in Figure 5 has'a yoke-shaped forward end in which" the die.

30 is disposed. The support is mounted atop a'base 58-; A-pivotpin-'5 fis connected withtthe base 50 and projects upwardlytherefrom. The pivotpin =5 I" enters'a bore "iniztheisupport 49 whereby topositionthesupport-49 upon'the base ofth'e pin 5 I '(Figure'QIz' Thus'I provide for.pre=v cise angular adjustmentof 'the dief 3fl*"for. co: operation withthe die 2 9- whose: position is. fixed.

Thebase-- 50 -has-opposed-' upwardly" projecting t. portions 52 and '53.The support: :49 has *two: crossr' bores 54ineach'"of. which ispositioned a pin-551. One end-of eachofithe pins '55 is adapt-. edtobear'against "the portion 52. Each of :the' bores 54 has atits-end'which -is-"adjacent theportion 53' "anenlarged and internally,threaded 5 portion-56. A screw 51 is threadedin'to seachof'i theportions 56 so that'its inner-end engages the adjacent ,end 'of'xthecorresponding pin '55. The portion 53 has openings 58 'ltherethrough 'toprovide for access to the screws 51'. The-screws S'F'may have wrenchreceiving :sockets. in theirv outer. ends; and a .wrenchsuch.assanAllenrwrench may be inserted through each opening. 58 s-tden-tgage and turnithecorresponding screw-r51. The angular;positionvof.the-support 49 .on. the base- 5E1 isqadjnsted by turning thescrews 51 tov exert pressure against or. relieve [pressure upon there-rspectiverpins Eds-the pressurea-ofgthe pins against the1391171011252 w=-causing gturnineeofsther f' support 49 aboutthe'axi-s,:..of -the Epin 5|: -unti1: it assumes; its; desired:adiusted:.-position:.. Atmthat. timeanutseare tightened:On.lb01l;&l;59iZOOIlIlfiGli(-3di. withcand extendinggunwardlyfrOm:.*the.base'-:50.;

maintain the support 49 indesired adjusted angular positionupon the base50.

The frame has a'guideway 6 I receiving a dove-- tailed guiding portion62'on the bottom of the" base-50-=so that the base tifl and everythingcarried-byitmay b'e-moved'toward and away from the-die-29.-* A-piston inacylinder 63 has a piston rod 64 connected w-ith the-base 53 so that:

upon movement ofthe piston-in the cylinder the base 5i3 is movedalongthe guideway 6! toward or-awayfromthedie 29 depending upon thedirectionof movement of the pistoninthe cylinder.

Thepiston-is-operated by hydraulic means presently to be described.Hydraulic actuation of the die til relatively to the'die29 has veryimportant advantages-over mechanical operation ofthe diesas mentionedaboveand as will be further developed below.

'Ihepiston rod 64 passes freely through a bore 64a in a bracket- 6417 lwhich is stationarily mountedon-the frame. Thepiston-rod 64 is threadedfora-portion of its --length and has two pairs of co-operatinglocknuts-84c and 6411; one pair'oneach side of the'bracket 64b.' Thelocknuts 64c limit' the movement of the piston inthe cylinder 63 when-the-die30 is retracted away from" the die 295 Thelocknuts 64o maybeadjusted to--difierent-positions when pipe of different diametersisbeingoperated-uponsoas to desirably limit *the stroke of -the piston andeliminate unnecessary-lost 'motionr The locknuts 64d havenofuncti'on innormal operation of the apparatus but maybe usedtolimitthe-forwardmovement of the piston during setting up; alsothey serve as a safetydevice-to stopthe piston in the event of die breakagepr other emergency.In Figures 5; 6; '7 and 8 clearance is shown between 65 in the dietill-(Figure 5) The flange and recess relatively fix ed axial position;Also, the radial dimensions-of the flange 34 and the recess 65 areproportionedsothat when the flange bottoms in the recess it limits themovement of the dies toward'each'other and hence limits the extent ofthe operation upon-the pipe. Thus I insure uni form and accurate threadformation.

3 Immediately behind-the flange 34 the die 29 has a radial recessfifi'against which two rollers- GT'bear to-counteract-the thrust againstthe die 29 ofthe die 30 when the latter is moved toward the former-w Thethrust bearings 61 are mounted "60.U'in' a head 68 mountedon the machineframe and adjustable'toward and away from the dies by adjusting screws69.

During operation-'of-the dies on the pipe the shaftBGturns inthe-clockwise direction when 'viewed -from the 'rig'ht-hand'end thereofin Figure-5. Thus-the tendency of the die 29, as will be ob'servedbyaconsideration of Figure 5, is to turn' out ofthe end-of the-pipeorconversely-to back the pipe ofi-ofthe die- -29 during threadformation: 'To-counteract that tendency the'die 30 is made of somewhatgreater diameter than the die 29 but the gearing isofnecessity arrangedso that both dies-'turn at the same angular veloc ity-butin oppositedirections. Thus during thread throughselongatedfislotsdilmn thessupport49ston75srormation the die w not 'oIIIy'co Operates'withwiforlimited.-rtuming.movement v the -45 has other functions. Itenters an annular recess arse -139 the die 29 to form threads in thepipe but also exerts a frictional force on the outside of the pipetending to turn the pipe onto the die 29 and thence prevent it frombacking ofi. Since the end of the pipe is disposed against the flange 34during rolling of the threads it is maintained in fixed axial positionrelatively to the dies during the thread forming operation.

The gearing is enclosed within a casing lit. Disposed within the casingand connected with the shaft 43 by a coupling H is an oil pump 12(Figure which picks up the lubricating oil from the bottom of the oilpan and delivers it through pipe (not shown) to the gears and bearings.

The shape of the dies is of great importance in the formation of myimproved threads. One of the dies is a thread forming die while theother die is a non-thread forming die which co-operates with the threadforming die to cause the metal of the pipe to flow into the threadforming die. The dies have complementary metal forming faces, the threadforming die preferably having thereon a helical metal forming projectionwhose side walls are substantially parallel to each other and thenon-thread forming die having thereon a helical metal forming projectionwhose side walls are inclined to each other, which inclined side wallsextend substantially to the crest of the second mentioned projection,the projections being in axially staggered relation. The projections areshown to greatly enlarged scale in Figure 11. In that figure the threadforming die is the die 29 since it forms the threads on the inside ofthe box end of the pipe. The dies for operating on the pin end of thepipe are reversed, the thread forming die being the outside die. InFigure 11 the outside die 38 is a non-thread forming die. The helicalmetal forming projection of the thread forming die 2% is shown at 73 andthe helical metal forming projection of the non-thread forming die 3%]is shown at M. The side walls 15 of the projection it are substantiallyparallel to each other while the side walls 16 of the projection M areinclined to each other and extend substantially to the crest l? of theprojection '14. The projections i3 and 7d are in axially staggeredrelation. The inclined side walls it of the helical projection i l onthe die 36 preferably have rounded corners "i8 and '19 at their top andbottom extremities respectively. The dimension of the projection Maxially of the pipe at its crest is not over about half of the axialdimension of the projection 73. In between the convolutions of theprojection is the face of the die 3!] has a helical groove lid ofsomewhat dished shape merging through the rounded corners 79 into theinclined walls '36 of the projection M. Since the axial dimension of theprojection M at its crest is not over about half the axial dimension ofthe thread forming projection 73 of the die 29 the groove 88 is ofsubstantially greater axial dimension than the projection '13.

The end face 8| of the helical thread forming projection 73 is shown asbeing substantially at right angles to the side walls l5 so that thethread forming projection ":3 is substantially square as shown in Figure11. The dies co-operate so that in the threaded pipe the thinnestsection at the thread is at least about eighty per cent of the thicknessof the pipe wall at a point removed from the thread. I

The improved results obtained by my improved dies are realized to thefullest extent through the hydraulic actuation of the dies toward eachother. Hydraulic actuation plus the shape of the dies resuits information of a thread greatly superior to rolled threads heretoforeproduced.

As the outer die 3i} moves toward the inner die 29 and engages the outersurface of the pipe it first deforms or corrugates the pipe so that inits initial stages the pipe is wavy internally and externally likecorrugated iron culvert pipe. This corrugation of the pipe results inits being foreshortened, i. e., in its length being somewhat decreased.As the pipe is foreshortened the piston in the cylinder l4 moves forwarddue to the constant hydraulic pressure which i applied to it so thatduring the foreshortening process the box end of the pipe is at alltimes maintained firmly against the flange 34. The foreshortening andcorrugating process may continue for a number of revolutions, saytwenty, until the inner faces of the corrugations engage the bottom ofthe groove between the convolutions of the thread forming projection'13. At that time the hydraulic pressure on the die allows forcommencement of flow of the metal of the pipe without shearing of themetal. The non-thread forming projection M with its inclined faces androunded corners causes the metal of the pipe to flow somewhat axiallyalong the groove between the convolutions of the thread formingprojection 73 to fill the corners of the groove and thus produce asquare cornered thread. Continued hydraulic pressure consolidates andsolidifies the metal so that a strong compact metallic structureresults.

During the thread formation the metal is squeezed so that it is causedto flow without any substantial shearing to form threads projecting fromone surface of the pipe while the opposite surface is deformed; thus themetal throughout the entire thickness of the pipe is flowed and reshapedduring thread formation. The metal flow is limited at the crests of theincipient threads and the metal is forced laterally generally parallelto the crests to form the generally square thread corners.

Figure 10 shows a joint between two sections of pipe having threadsrolled thereinto in accordance with my invention. The section 82 has aninternally threaded box end 83 and the section 84 has an externallythreaded pin end 85. The internal threads in the box end and theexternal threads in the pin end are of substantially the same formexcept that the internal threads face inwardly and the external threadsface outwardly. Since the threads are substantially square they interfitvery accurately and provide the maximum resistance to pulling out. Also,due to the form and proportions of the threaded pipe ends as aboveexplained, the joint is exceptionally strong in tension tests tofailure.

The thread proportions and dimensions are determined by the dies andare, of course, the same as the proportions and dimensions of the dies.The surface of the pipe opposite the thread. has a helical depressionWhose dimension axially of the pipe at its bottom is not over about halfthe dimension of the thread axially of the pipe and the depression isdisposed radially opposite the center of the thread crest. A helicalprojection is disposed radially opposite the thread throat. Theprojection and depression merge into each other through rounded corners.The helical projection opposite the thread throat has a dimensionaxially of the pipe at least one-third greater than the dimensionaxially of the pipe of the thread throat. The side walls of the helicaldepression opposite the thread crest are inclined toward each. other andextend substantially to removed :from they thread.;

The operating and controlling mechanism is 7 shown in- Figure 4; The oiltank forthehydraulic actuating mechanismis shownxat 86.1 The; pump forplacing the oil for thehydraulic vcyline. I ders under pressureis-shownat 8 1. Oil 'isdrawn out of the tank-86through a1pipe-88-andis idelivered from the pump 81through-apressureline 89 towae way valve9lli'having a valve operating:

The valve may beof conventional-forma Whenthe die-30 is to be movedtoward the'die- 29 the valve 90-is operated so that thefliiiddrom thepressure line 89 passes through a -pipe-92 to the outer end of the:cylinder 63 to push thepiston in that cylinder in the upwarddirection'view ing Figure 5; The fluid in front ozf the piston- J to-a'T94 in a pipe 95:- A one-way=-valve-96:permits flow-of fluid only-fromright toleftand not from left to rightin the pipe 95 viewing-Figure.

4. Therefore, the fluid passing downwardly lever ,9 l

passes out ofthecylinder-63 through a-pipe 93 through the pipe-934sconstrained to move to the left in the pipe 95.

The pipe 95 delivers-the fluid-to a flow-controlling throttle valve-S]having an adjustment device fifi; for controlling the opening therein sothata-desired amount of throttling of the :fluid:

passing tothe valve 91 through the pipe-95qmay be obtained- Fluidleaving the .valve 91 passes through a-pipe I and baclginto. the :tank-86. Thus the throttle valve 91 is effective tothrottle or slowdown, theflow of fluidirom in front-20f the-piston in the cylinder 63 ,when; thedie :3flviS being moved toward the die 29.; By a-proper setting ofthetvalve 91 thedesired speed ofrmovement of the die 30 toward the-die29 may-,beobtained so as to bring about the proper metal ,flowg.However, the-hydraulic system is such that when the die fifluiswithdrawn away from the=idiew29 the throttle valve 91 does not :functionso that thespeed of withdrawal may begrapid-and;;in dependentofthe speedof advance. Whemthe die 30 ;is-to ;be withdrawn awayjrom the :die :29the valve Qiiris moved to the-,position inzzwhich thefluid underpressure from the pipe 89 passes out of the valve through the'pipe 'lflland thence through thexone-way valve-flfiinto-the Ti94. Due to thethrottling effect of the valve 9'! the .fluid pass s pw y h u h hespipe93 and'iintc the-cylinder at th ide oi thezpistonznearest the die 30.The fluid fromtthe sidehof the piston remote from the die 30*passesoutof the cylinder through the pipe 92 through the 4-way valve flflandvbackto the pipe- I 00=through a pipe I02.

There is provided a source :of compressed air which, passes throughapipe--'=l'03"-to a valve 104 controlled by a treadle I05. Dependingupon the position of the treadle the valve l 04 may direct the air underpressure through either of two pipes I 06 and I01. Those pipes leadthrough pipes I08 and H19 respectively to the lower and upper ends ofthe cylinders 22 so that by operation of the treadle I the actuatingmembers I! are operated. Only one of the cylinders 22 is shown in Figure4 but the pipes I06 and ID! are connected with both of such cylinders inlike The source of compressed air is connected through a pipe H0 with ahand operated valve Ill so that the compressed air may be deliveredthrough either of two pipes H2 and H3. Those pipes lead to therespective ends of the cylinder 114 llisotthat tdepeadine :upcmtheapositiom frthee valve 1H icompressedairimayvmoyetherpiston-im thecylinder: 1 4 :in:eitherrdirection; The zfunction accomplished: by-.-their movement: has: 811-, ready beerrexplainedza.

The. shatt :36emay-fibe driven: through the. 5 .0013: pling. 3B yby: anelectric; motor .1Msthrough.,.a; suitable. gean reducer.Theepumpltilrmay her operated byaan electriclmotoneither on-thesamesshaft or; gearedr togthe pump: shaft; l llectricalv energy may bedelivered to 1 a switch :box: 1 I52; through wires not shown) passingthrough nan;- inlet conduit I it; and to the respective motors through.conduits .l l l :and through; :a;- conduit :1 .l 8 to control switches:H 9::- Theaelectrical control system1may=.be-'conventional.:

tau-pipe 'GXldviSHtO' bezthreaded ithesdie 130.: is :movedaway: from:thie.=.dier29;- awpipe end is; introduced over the die 29 :as; aboveexplained,i. the dies and pipe @are rotated and .1 during ,suchz-vrotation the die 30 wis:moved::against theioutsides: of the. pipe end:opposite: die; 29 :as above; explained to roll threadsintothe pipeend.When; the thread-ing has been completed. the die Bitmapbe :retracted andthe apipeoslowed Cup: 1 relatively-'- to: the die- 29 manuallymrotherwiserwhereupon the threaded pipe automatically backs off of :the;die 29. This is a rapid way of removing: as: threaded pipe irom the die:If desired-ztheirotation of thed-i'es may bestopped'and thepipe mayobe-turned off of 'the di'e 29. Thecdiiesumaygblee rotating or stationarywhenathe apipe. end-11s price sentedthereto prior tos three.ding:-

My metal pipe-having agroiled thread is claimed;

: in'my divisional-application Serial 18!);828;

filed October 12, 1950.

While'I have shown and describ'ed;present:

preferred embodiments of invention and: a.-.;

present pref erred method of-practicing the same;

it is to be distinctly understood that the .invene tion is not limitedthereto-"but may be otherwise 1 variously embodied and": practiced 1within the; scope of the foll'owing :clairnssv I claim:

1. In-a machine for rolling-threads intoi metal: pipe, a-rotary dieadaptedto be'posi-tioned' insidex a pipe end, the die beingmountedhfor-rotationw about afixed axis, a second -rotary'v-die adaptedto be positioned outsidethe-pipeend; a 'support: in which the second-die is mounted a base ;on which the support is pivotally mounted, thebase being movablegenerallytoward and away from the first mentioned die;and means for maintai-m ing the support in: desiredangularposition-aboutits pivotal mounting; on the-base:

2; In a machine for'rolling threads intometalpipe, a rotary .dieadapted,to be ppsitionedinside apipe end, the diebeingmounted 'for rotation"about a fixed axis; a second rotary di'e'adapted to be positionedoutside the pipe end, a support in which the second die is mounted, abase on which the support is pivotally mounted, hydraulic means formoving the base toward and away from the first mentioned die, means formaintaining the support in desired angular position about its pivotalmounting on the base and means for adjustably positioning the baserelatively to the hydraulic means in the direction of movement of thebase.

3. In a machine for rolling threads into metal pipe, opposed rotary dieshaving complementary metal forming peripheries, one of said peripherieshaving thereon a helical metal forming projection comprising a pluralityof convolutions having in axial cross-section a substantially flat crestextending generally parallel to the axis of the die and substantiallyfiat side walls substantially perpendicular to said substantially flatcrest forming a depression between adjacent convolutions of theprojection, the bottom of said depression being substantially flat inaxial cross-section and extending generally parallel to the axis of thedie and joining the side walls of adjacent convolutions of theprojection, and the other of said peripheries having thereon a helicalmetal forming projection comprising a plurality of convolutions directlyopposed to the helical depression of the first mentioned periphery, thehelical metal forming projection of the second mentioned peripheryhaving in axial cross-section an elongated substantially fiat crestextending generally parallel to the axis of the die whose dimensionaxially of the die is not over about half the dimension of thedepression of the first mentioned periphery axially of the die andoutwardly inclined side walls with rounded corners at the top and bottomextremities of the side walls, said elongated crest being of sufficientlength to force the metal of the pipe into said first mentioneddepression and against the bottom thereof and the side walls being sorelated as to create axial flow of said metal to fill the corners ofsaid first mentioned depression.

4. In a machine for rolling threads into metal pipe, rotarycomplementarily threaded dies adapted respectively to be positionedinside and outside a pipe end when the pipe end is presented thereto andto cooperatively roll threads into the pipe end, means for supportingsaid dies so that the outer end of the inside die is unsupported topermit the pipe end to be introduced endwise thereover, the inside diehaving a radial flange located inwardly of the threads thereof at apredetermined distance and spaced from the unsupported outer end thereofacting as a stop to limit the extent to which the pipe end passes overthe inside die and thereby determine the location of the threads in thepipe, and the outside die having a radial groove receiving the radialflange of the inside die to maintain the dies in relatively fixed axial.position during formation of the threads in the pipe.

5. In a machine for rolling threads into metal pipe, rotarycomplementarily threaded dies adapted respectively to be positionedinside and outside a pipe end when the pipe end is presented thereto andto cooperatively roll threads into the pipe end, means for supportingsaid dies so that the outer end of the inside die is unsupported topermit the pipe end to be introduced endwise thereover, means acting onthe outside die to move that die transversely of its axis toward theinside die, the inside die having a radial flange located inwardly ofthe threads thereof at a predetermined distance and spaced -from theunsupported outer end thereof actin as a stop to limit the extent towhich the pipe end passes over the inside die and thereby determine thelocation of the threads in the pipe, and the outside die having a radialgroove receiving the radial flange of the inside die to maintain thedies in relatively fixed axial position during formation of the threadsin the pipe, the radial dimensions of the flange and groove beingproportioned so that the flange bottoms in the grooves uponpredetermined movement of the outside die toward the inside die wherebyto limit the extent of action of the dies on the pipe, and roller meansacting against the portion of the inside die at the side of the flangethereof remote from the outer end of the inside die and remote from theoutside die supporting the inside die against bending caused by theaction of the means for moving the outside die toward the inside die andthereby minimizing deflection of the inside die during rolling ofthreads in the pipe end to effectuate the limiting effect of said flangeand groove.

HARRY J. FINCH.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date Re. 9,908 Blakeslee Oct. 25, 1831 9,732 Muntz June 14,1853 326,516 Pierce Sept. 15, 1885 350,853 Anderson Oct. 12, 1886421,625 Sims Feb. 18, 1690 509,730 Grifiin Nov. 28, 1893 748,276 GabrielDec. 29, 1903 768,771 Riegner Aug. 30, 1904 798,448 Pogany et a1. Aug.29, 1905 859,642 Cummings July 9, 1907 1,033,568 Fell July 23, 19121,330,316 Hall Feb. 10, 1920 1,544,057 Dimick June 30, 1925 1,804,686Hall May 21, 1931 1,936,401 Lovely Nov. 21, 1933 2,054,182 Unke Sept.15, 1936 2,122,525 Huntsman July 5, 1938 2,145,587 Draper Jan. 31, 19392,182,401 Kreis Dec. 5, 1939 2,312,225 Wilkinson Feb. 23, 1943 2,352,726Maulding July 4, 1944 2,365,820 Hibbard Dec. 26, 1944 2,405,141 HibbardAug. 6, 1946 2,610,532 I-Ieppenstall Sept. 16, 1952 FOREIGN PATENTSNumber Country Date 12,373 Great Britain 1848 28,465 Great Britain Apr.25, 1907 893,456 France July 28, 1944

